I am contemplating between Tromso (Norway), Abisko (Sweden) and Rovaniemi (Finland).
While Tromso is perhaps the most well-developed in terms of tourism infrastructure (and other activities to do) out of the three, it seems lights are best seen from Abisko due to least pollution and colder weather.
Can someone provide first hand suggestions?
This question is opinion-based, but I would certainly go for Abisko. But why not make it a trip and visit all three?
Abisko and Rovaniemi are both pretty good but Abisko is in the mountains and near the coast, and has more natural scenery to offer. Rovaniemi has the santa claus village. Tromsø has the prettiest scenery but the least favourable climate for northern lights, although if you go inland a bit to Bardu conditions are essentially identical to Abisko.
If you prefer natural scenery, go to Abisko to see the lights and spend the day looking at natural scenery, either from Abisko or from the sky station. Abisko has a nice canyon, is next to a beautiful lake, and has generally a beautiful valley with Kungsleden leading south, which is good for hiking or cross-country skiing.
If you prefer santa claus village and tacky souvenir shops, go to Rovaniemi to see the lights at night and the santa claus village during the day. You can also spend some time exploring the surrounding hills/forest.
I boarded the Hurtigruten at Tromsø and we viewed the borealis from the sea on the way to Kirkenes. It was nice because on the boat we were away from many of the lights of the built up areas.
The biggest concerns for seeing the northern lights are 1) to be as far north as possible; 2) for it to be dark; and 3) to be free of cloud.
So, Tromsø would be the obvious best bet because it is so much further north. To ensure darkness, do not travel at midsummer and if you choose a wintertime trip, that will maximize your chances. To be free of cloud, you simply need to maximize the dark hours spent on the ground there.
Another consideration would be to choose seating, route and flight times in darkness, so that if the ground visit is obscured by cloud cover, you may have a good view of the borealis from the airplane.
